I agree with maljo. I have been using Aperture 3 for the past 3 years. Before I was using LR, started with V1.0.

I found A3 a very capable app and occasionally I use LR5 when I have the urge to see how the processing compares to Aperture, but I have never felt LR made a difference. I have developed a preset in Aperture and refined it over time, which makes RAW processing very fast and require only fine tuning.